Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual era o modelo para a classe PRR de frete gf28a?
 ###Tabelas: CREATE TABLE professional_seasons_1994-2003 (professional_seasons_1994-2003_id AUTO_INCREMENT PRIMARY KEY, Season INT, Winners VARCHAR, Runners-up VARCHAR, Third-place VARCHAR, fourth-placed VARCHAR, Number of clubs INT) CREATE TABLE construction_and_seating_capacity (construction_and_seating_capacity_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Stadium VARCHAR, Capacity VARCHAR, Location VARCHAR, Home Team VARCHAR) CREATE TABLE wga_awards (wga_awards_id AUTO_INCREMENT PRIMARY KEY, Year INT, Category VARCHAR, Nominee(s) VARCHAR, Episode VARCHAR, Result VARCHAR) CREATE TABLE general_electric (general_electric_id AUTO_INCREMENT PRIMARY KEY, PRR Class VARCHAR, Builder’s Model VARCHAR, Build date VARCHAR, Total produced INT, Wheel arrangement VARCHAR, Service VARCHAR, Power output VARCHAR) CREATE TABLE inhabited_territories (inhabited_territories_id AUTO_INCREMENT PRIMARY KEY, Territory VARCHAR, Abbr. VARCHAR, Capital VARCHAR, Acquired INT, Territorial status VARCHAR, Population ( 2010 ) INT, House seat INT)  
SELECT Builder’s Model FROM general_electric WHERE Service = freight AND PRR Class = gf28a